The present invention relates generally to portable power tools, and more particularly relates to hand-held portable blower units used, for example, to remove grass clippings, leaves, debris and the like from sidewalks, driveways and other generally horizontal surfaces using a high velocity discharge air stream generated by the unit.
Hand-held gasoline engine-powered blower units of this general type are now quite common and are utilized to blow away a variety of ground debris. The typical unit comprises a hand-held housing secured to an elongated air discharge tube. A small gasoline engine disposed within the housing is used to rotationally drive a fan impeller which draws in ambient air and discharges the air, at a relatively high velocity, through an elongated discharge tube secured to the housing structure. By aiming the discharged air stream at ground disposed debris, such as leaves or grass clippings, a rapid cleanup of sidewalks, driveways and the like may be effected.
A variety of well known problems, limitations and disadvantages are typically associated with conventional hand-held blower units of this general type, including undesirably high weight and bulk, handling difficulties,
high engine noise levels, and engine choke/throttle coordination complexities often presented to the unit's operator.
For example, the usual engine, fan impeller and pull-starting system arrangement and configuration typically incorporated in conventional hand-held blower units tends to make them rather heavy and, due to the overall size and bulk of their engine and fan shroud housing, somewhat unwieldy to use. Moreover, the gyroscopic force effects arising during engine operation can render positional control of conventionally configured blower units somewhat difficult.
Conventional hand-held blower units of this general type are typically provided with separate engine throttle and choke controls which are independently adjustable by the unit operator. For each engine operating condition, and particularly during a cold start-up condition, there is a generally optimal relationship between the choke and throttle setting for the particular engine. However, particularly for an inexperienced or unskilled blower unit operator, precise matching of such settings across the full throttle to full choke range of engine operating conditions is often difficult to achieve using the typical independent throttle and choke adjustments.
Finally, while the typical blower unit's engine exhaust noise is conventionally attenuated using an exhaust muffler, it is often the case that the engine's air intake noise remains unacceptably high.
In view of the foregoing, it is accordingly an object of the present invention to provide a hand-held blower unit in which the above-mentioned and other problems, limitations and disadvantages are at least substantially reduced.